Method of granulating molten slag



- Jan. 22', 1929.y

' 1,699,575 F. w. E. sPlEs METHOD o? GRANULATING norman SLA@ Filed M194, 1927 Patented Jan. 22, 1929.

UNITED 'STATES FRIEDRICH WILHELM EMIL SPIES,

0F VELSENNOORD, ANETHERLAN DS.

METHOD 0F GRANULATING'-MOLTEN SLAG.

Application led August 4, 1927, Serial No. 210,683, and in Germany Hay 16, 1925..

-My present invention relates to a method of granulatin g molten slag, for instance, from -a blast furnace, its object being to obtain, with a minimum of cost, a practically dry product of sufficiently glassy character and. suitable for the manufacture of cement,'bricks and the like. v

With this object in view, I bring the molten slag into contact with a relatively small quantity'of water, for'instance, of from 300i- 500 litres per ton of finished roduct, whereby the molten slag is strong y. cooled` down and converted into a'spongy mass, and the Water entirely or for by far the greater part evaporated. This spongy mass, while still comparatively hot, is exposed to the action of a jet or stream of relatively cool gas,

preferably air derived from the cold blast main, whereby it is further cooled down and changed into finely grained material.

Over the so-called moist granulation, my

method has the advantage of working without, or with only a very small excess of water and of yelding a substantially dry material, yet Without requiring cooling drums or other mechanical appliances that are liable to heavy wear and tear. Consequently, with my novel method both the power and the water consumption are minimized, which is remarkable in Vview of the exceptionally high grade product, which is a fine, porous material without big lumps. Moreover, my method can be carried out in an installation which vrequires very little floor space.

n In order that my said 'invention may be fully understood by. those skilled in the art,

I shall now proceed to describe the same with reference to the annexed, more or less diagrammatic drawing, which illustrates, by way of example only, an apparatus Iin which my process'can be carried out. On this drawiig. 1 is a front elevational view,

Fig. 2 is a longitudinal sectional view, and Fig. 3 is a plan view of said installation.

The molten slag from the blast furnace, or

-from any other source, is fed bythe usual slag runner V1 onto a slightly downwardly sloping shoot 2, the walls of'fwhich are coated with cast iron wearin plates 2a. Over'ffthe bottom of this shoot ows a stream ofcold water 'ejected from a nozzle at the end of a cold water supply pipe 3 provided with a valve 3". n' When coming into contact vwith Vfrom va blast furnace, brin g this cold water and with the steam generated therefrom, the molten slag is suddenly cooled down to say 600o C. and converted' into a.

'spong dough-like mass. The supply of cold Water is .controlled in such a mannerthat the quantity of Water just suflices to turn the molten slag into a semifinished product of the above said properties. As already stated above, a quantity of SOO-500 litres of water per ton of finished product will ordinarily prove to be satisfactory. The excess of water,

if any, is drained through two short, lateralbottom is a nozzle 4** forming the end of a pipe- 4 connected with a suitable source of compressed air, forinstance, the cold blast main, although it should V4be understood that it may also be connected with a source of other gas, or vapour, for instance, steam. The nozzle 4 is upwardly inclined, its mouth being elongated in a'vhorizontal directionkat right angles to the longitudinal axis of the shoot 2, so that the still hot, spongy mass falling from the shoot is spread out and blown away in an upf,

wardly inclined stream 5, the consequence being that said mass isjbroken up andcooled down. The product thus obtained is a sub stantially dry,.nely ranulated, porous mass of high quality, whic by the jet of air, is delivered into a storage bin or the like.

By adjusting the distance between the end of the runner-l and that of the shoot 2, I may regulate the time during which the molten slag is in contact with the water.

What I claim is "1. In a method of granulating molten slag,

.bringing the molten slag into contact with water so =as to convert it into a spongy mass, and exposing said spongy mass to the action of a relatively cool gas stream so as to change 'it into substantially dry, granulated material.

2.v In a method of granulating molten slag the molten slag into contact with a relatlvely small quan- 2tity of water so as to convert it into a spon y mass, and exposing saidspongy mass to t e action of a stream of'cold alr derived from the cold blast main so as to change it into substantially dry, granular material.

3. In amethod of granulating molten slag, allowing the molten slag to flow through a conduit in Contact with a relatively small quantity of water so as to be converted into a spongy mass, and thereafter allowing said spongy mass to flow into the path of a relatively eool gas stream s0 as to be changed into substantially dry, granulated material.

4. In a methodof granulating molten slag, allowing the molten slag to flow through a downwardly sloping shoot, flowing a relatively small quantity of water into Contact with the molten slag in said shoot so as to convert the same into a spongy mass, and allowing said spongy mass from said shoot to fall into Contact with an upwardly inclined stream of relatively cool gas whereby it is changed into and blown away as substantially dry, granulated material.

5. In a method of granulating molten slag, allowing the molten slag to flow through'a downwardly sloping shoot, flowing a relatively small quantity of water into Contact with the molten slag in said shoot so as to convert the saine into a spongy mass, allowingy said spongy mass from said shoot to fall into contact with an upwardly inclined stream of relatively cool gas whereby it is changed into and blown away as substantially dry granu.- lated material, and allowing the excess of water to separate from the spongy mass before said mass is exposed to the action of the gas stream. y

In testimony whereof I aflix my signature.

FRIEDRICH WILHELM EMIL SPIES. 

